Some people feel as though they have the flu for a few hours to a few days after chemotherapy treatments. This may be especially true if you are receiving chemotherapy in combination with biological therapy. Flu-like symptoms - muscle and joint aches, headaches, fatigue, nausea, slight fever, chills, and poor appetite - may last from 1 to 3 days. An infection or cancer itself can also cause these symptoms. Check with your doctor if you experience flu-like symptoms.